Spurred in part by the phony 70News.com site, which itself spurred an overnight change in how Google and Facebook are doing business, Zimdars, an assistant professor of communication and media at Massachusetts’ Merrimack College, published her own tally of questionable news sites. Her list of about 130 problematic “news” sites includes those she considers to be “false, misleading, clickbait-y, and satirical ‘news’ sources.”

Little did she realize she was walking into a maelstrom of controversy, uncharacteristically speedy Silicon Valley reaction, and that bigger debate about how the new gatekeepers of our news should behave. I described that firestorm Tuesday.

On Monday, Zimdars had prepared for her Introduction to Mass Communications class. Over the past few weeks, she’d been compiling a Google Doc, a list of sites that didn’t seem trustworthy. “It seemed like we need a list of criteria for web-based news,” she told me Tuesday. “I didn’t see a database that allows to do that. I was just trying to create an overview.”

The list grew and grew and, good instructor that she is trying to be in her second year of teaching, she wanted her students at the conservative-leaning school to evaluate the sources of their news. “I wanted them to look at media bias,” she says, “but also at corporate bias, and any other bias that people bring to their sites.”

In addition to sharing the list with her students, the 31-year-old prof shared it on Facebook. She changed her setting from private to public, and has since joined the now-raging debate, and anger, over fake news. By Tuesday evening, she’s seen 22,000 Facebook shares and guesstimates a thousand or more on Twitter.

The response, while surprising, isn’t astounding. Public disdain with fake news began boiling as Donald Trump’s victory became apparent. How could it happen — who and what was to blame?

Hillary Clinton’s failure has many fathers — an unlikable candidate, poor get-out-the-vote strategy, Bill Clinton’s heavy baggage, FBI director James Comey’s interventions, Vladimir Putin’s behind-the-scenes string-pulling — but it is Facebook that has found itself caught square in the crosshairs of rage. All of sudden — after a number of years of smaller-scale complaints — the masses had come to reckon with the question of how little some of Facebook’s content could be trusted.

Though Facebook CEO Mark Zuckerberg had tried to dismiss the notion that his site enabled the Trump victory as “crazy,” the pressure had mounted — on social media, of course. Then, internally at Facebook a quick skunkworks project to deal with “fake news” got to work. As Facebook (situated in California’s Santa Clara County, which gave Hillary Clinton 73 percent of the vote) scurried internally, Google goofed, and the Washington Post captured the error. Then, in real-time, later on Monday both Google and Facebook moved to do something they should have done long ago: proclaiming that they would no longer let fake or phony sites — in Google’s words, ones that “misrepresent, misstate, or conceal information” — use their powerful adtech platforms to sell ads on those sites. Neither behemoths, seeing the digital mob forming, wanted want to find themselves on the wrong side of history.

It was that publication of the 70News misstep that served as the final impetus for Zimdars to publish her list, she says. That list is more than a curiosity. While its inclusions — from Breitbart to Upworthy and The Onion to The Blaze — can be (and already have been both publicly and in emails to Zimdars) richly debated, it is the creation of the list that is more important.

The stunning realization that some voters made their choices based on lies, and that the slim margin in this presidential vote may have profoundly changed the direction of the country and the globe, hit home. These issues aren’t new ones — and they get to the issue of provenance in the hurly-burly world of digital news media that will finish replacing much of the print and broadcast one over the next 10 years.

Where does news come from? What is true? What isn’t? What’s the agenda, if there is one, of the publisher? These are all the questions Melissa Zimdars would like her Intro to Mass Comm students to consider — even as she offers up that question square in the face of the wider public.

The Zimdars list is incomplete and review and requiring better categorization (for instance, separating satire from “fake”) — as she’s the first to suggest. Further, a look at the list on Tuesday included several “*Website Removed* (temporarily)” placeholders, as she reviews again due to web reaction: “There’s a lot of stuff in weird, gray areas.” Zimdars lists her own initial criteria on her list.

(Update: At midday Wednesday, six of the initial sites listed had been replaced with “*Website Removed* (temporarily),” as Zimdars decides how to proceed with the list. Among those removed is Upworthy, an aggregator of progressive-leaning content, which had been included for using “clickbait-y headlines.” These in-process decisions point to the problem of mixing together “misleading” sites with “clickbait-y” ones. Zimdars’ experiment will likely then have value as just one first example of defining the problem, a list, or set of lists, for others to refine.)

Still, it offers a beginning answer to Zuckerberg’s emerging dilemma. He doesn’t want Facebook — that global, free, and open platform — to be an arbiter of what’s legit and what’s not. But if Facebook is now going to prohibit fake news sites from using its ad network to sell ads, it will need a list of its own. Just as on Tuesday both Twitter (harassment) and Tinder (gender identity) tweaked their platforms, given social pushback, Facebook must evolve its own standards over time. It’s a tough business, but it’s a requirement forced upon it by its own success.

Google has long had its own list of legitimate news sources, as it put together Google News, but it hasn’t apparently wanted to cut into its own profits by denying fake news sites the ability to use its ad networks. Now it will, it says — but we will be left to wonder: Who’s on its list, and why? While in newsrooms throughout the world, the choice and presentation of stories is fairly transparent, Facebook and Google — which together constitute the primary sources of new readers to the real news sites — retain their major capacities for opacity.